Which one of the following molecular hydrides acts as a Lewis acid ?
Which one of the following molecular hydrides acts as a Lewis acid ?
$\mathrm{NH}_3$
$\mathrm{H}_2 \mathrm{O}$
$\mathrm{B}_2 \mathrm{H}_6$
$\mathrm{CH}_4$
Solution
Key Idea:- Electron deficient molecules behave as Lewis acid.
Among the given molecules, only diborane is electron deficient, ie, does not have complete octet. Thus, it acts as a Lewis acid.
$\mathrm{NH}_3$ and $\mathrm{H}_2 \mathrm{O}$ being electron rich molecules behave as Lewis base.